Resonant fiber optic gyroscopes (RFOGs) have better rotation sensitivity for a given diameter than laser ring gyroscopes and interferometer fiber optic gyroscopes. Thus, RFOGs are desirable because a given level of rotation sensitivity can be achieved with smaller RFOGs, reducing the size of inertial navigation systems incorporating RFOGs. RFOGs, however, are susceptible to bias error because of imperfections in RFOG optical components and parameter mismatches between RFOG signals.
One source of bias error is polarization mismatch between the polarization Eigenstate inside a resonator of the RFOG, and the polarization of light being injected into the resonator of the RFOG. A pair of polarizers is used polarize light circulating in the resonator and light injected into the resonator, e.g. in each of the clockwise and counter-clockwise paths. Polarization mismatch arises because of differences of polarization of the polarizers within a pair. The differences may arise due to variations in manufacturing of each of the pair of polarizers, and their installation in the RFOG. Therefore, there is a need to reduce polarization mismatch.